I just had my pully belt changed it was making a squeaking noise when i start it up there is no noise but after the car warms up it makes a little squeaking noise not as loud as before but still there and the other problem i have is there is a plastic shield siiting behind the engine it has carroded the heater hose is still intact just a piece of the front bit is this urgent to replace and is tis common in this series thamks

I can't say for sure but it could be the tensioner pully. I don't think you should be able to move it side to side. That would indicate that the bearing is worn.

My guess is a pully is going bad on the tensioner. The new belt had more grip so it was able to force the bad pully to turn but now that the new belt is a bit worn it's beginning to slide as the pully gets worse...Does tha make sense? Solution: Remove the belt and turn each pully by hand. The pully's should turn very easily without ANY struggle. If you find a pully that has any stiffness ...(Or is hard to turn).....thats the bad one. Replace the bad pully and you will be a happy camper

it is your belt it needs to be replace you can buy belt dressing spray to use but if you have lot of miles I would replace the belt good luck..

bad crank pully, check to see if the lower main pulley is wobbley or the belt tensioner

2007 its your drive belt,let the dealer inspect for wear or if its loose,they are not going to reproduce it they are just sending you air, but hold them accountable for the drive belt and just ask ,"hey is this belt okay and I am not going to breakdown".

The only cure to fix squeaking belts, is to replace with the new one. When the belts start squeaking noise, then it is the time to check the status of the timing belt or chain, depending on the size of the engine.
The 2000-2004 Nissan Xterra was offered with the choice of 2.4L 4-cylinder or 3.3L V6 engine.
The 2.4-liter 4-cylinder DOHC engine was a pretty good reliable engine, but for this truck, it was underpowered. This engine has a long-lasting timing chain - there is no timing belt to replace.
The 3.3-liter V6 SOHC was also a bit slow on pick-up, but for daily use, it was pretty good, durable, simple engine. This engine has a timing belt that needs to be replaced at recommended intervals. The SE model offered a supercharged version of the same engine with more power.
To get more information, please read my tip :
When should I change the timing belt on my car?
http://www.fixya.com/cars/r6481199-when_change_timing_belt_car

If you didn't replace the belt at the same time, it is likely the belt that is causing the noise even if it "looks" ok, I'd suggest you replace it.

It very well could be the pawer steering pump. But to isolate the squeking sound, take that can of wd-40 and find the idler pully and tensior pully. Spray the bearing area of both pulleys. If your bearing in those pulleys are going bad then it will make that noise. If the wd-40 quits the noise at one of those tow pulleys then you know which one to replace. If its does not, then start looking to replace the powersteering pump. I take it you have checked the power steering fluid levels and they are ok?? Also, you stated that the noise started after you bought the alternator, then try a new alternator. It might of just been a faulty alternator. Happens all the time. One last inexpensive tip is replacing all belts with new. Belts get glazed over and dirty and cause noise too. One last question. Did you make sure the belts were tight enough? Just a little variance in the belt tension can make the difference.

Sounds like your fan belt and tensioner needs to be changed. Check your tension pully, they are known to fail and the belts start to slip. good luck and hope this will help you.

the ac belt is sperate from the power steering belt.. sounds to me you need to replace the belts (both of them) but theres a idler pully in the middle of them all witch may have a bearing going out on it..i had to change mine at about 85,000.. when i had the belts off i spun the pully and it was excessivly stiff cause'n slipage and also a squel.. hope its not the alt, or water pump making the noise..they can run ya into some $$